자체생산과 외부조달이 혼합된 조립시스템에서의 부품생산일정계획에 관한 연구

하귀룡(Gui Ryong Ha),윤상흠(Sang Hum Yoon) 한국생산관리학회 2008 韓國生産管理學會誌 Vol.19 No.3

  본 연구의 목적은 각 제품이 여러 개의 부품으로 구성되고 부품들은 내부생산설비를 통해 자체생산 되거나 외부생산설비로부터 외주되어 조달되는 경우에 제품의 최종 조립일정을 효과적으로 지원할 수 있는 자체생산부품에 대한 생산일정계획을 도출하는 것이다. 외주조달부품은 사전에 정해진 계약에 따른 조달시점에 도착되므로 자체생산부품의 생산일정을 이러한 외주부품의 조달일정과 조화시키는 것은 전체 조립일정의 효율성을 좌우할 수 있는 중요한 의사결정문제이다. 따라서 본 연구에서는 각 제품의 완료시간을 그 제품에 속한 모든 부품이 생산·조달되는 시점으로 모델링하고 전체 제품의 완료시간의 합에 해당하는 총 완료시간을 최소화하는 것을 일정계획의 목적함수로 채택하였다. 본 연구에서는 먼저 주어진 일정계획문제를 해결할 수 있는 분지한계 알고리즘을 개발하였다. 이를 위해 먼저 제품 간의 우선처리순서를 규명하기 위한 두 가지 우월성질을 제안하고 전체 수리계획에서 제약조건을 만족하는 해의 특성규명을 통해 효과적인 하한값을 도출하였다. 또한, 대형문제의 해결을 위한 효과적인 휴리스틱 알고리즘도 제시되었다. 제안된 우월성질, 휴리스틱, 분지한계 알고리즘의 성능은 다양한 수치실험을 통하여 검증하였다. 본 연구는 관련된 기존연구에서 한 개의 자체생산 부품만을 고려하였던 것을 여러 개의 부품을 고려할 수 있도록 확장한 것이며, 내부와 외부를 병행하여 부품을 생산 또는 조달하는 많은 주문생산방식의 조립생산시스템 현장에서 효과적인 부품생산 일정계획 수립에 활용이 가능할 것으로 판단된다.   This paper considers a fabrication scheduling problem to minimize the total completion time of a finite number of products in the fixed layout assembly system. Each product(or order) is composed of multiple components, and the components are manufactured on the in-house(and dedicated) facilities or outsourced with product-dependent lead times. This paper investigates the processing sequence for the in-house components to coordinate with the outsourcing schedule. The completion time of each product is measured by the time when all the components are completed(or, available). In the problem analysis, new powerful properties are proposed and a branch and bound algorithm adopting the properties is also suggested. An efficient heuristic algorithm to find the approximate solution is also developed. The algorithm is proved to be more robust than the earlier version of Lee et al, (2006) through numerical tests.

기술혁신활동이 경영효율성에 미치는 영향 : Inverted U Shaped 모형

하귀룡 ( Ha Gui Ryong ),최석봉 ( Choi Suk Bong ) 한국품질경영학회 2018 품질경영학회지 Vol.46 No.3

Purpose: This study addressed the relationship between technological innovation activity and management efficiency of Korean automobile firms. We tested the hypothesis of non-liner relationship of innovation activity in relation to management efficiency. Methods: We discussed prior literature in the firm innovation strategy and management efficiency studies to provide better understanding of relationships between technological innovation activity and management efficiency. As a result, we developed develop and tested a model (Inverted-U shaped) capturing the non-linear impact of technological innovation activity. While we used R&D expenditure and patent registration data for measuring firms’ innovation activity, management efficiency was evaluated by using DEA(Data Envelopment Analysis). Results: Main findings of our empirical analysis indicated that the relationships between technological innovation activity and management efficiency was inverted U shaped. This implied that the relationship between technological innovation and management efficiency is inverted U-shaped non-linear, with management efficiency increasing up to a point, beyond which higher levels of R&D and patent registration activities led to a decrease in management efficiency. Conclusion: This study empirically assessed the inconclusive findings of previous research in the area of effects of innovation activities in relation to firm performance. The paper also provided theoretical and practical implications for firms who explore efficient strategy to promote the management performance through technological innovation activities. Future research directions with the limitation of the study was discussed.

코로나19 전후 국내 자동차산업의 경영효율성 비교 분석

하귀룡 ( Ha Gui Ryong ) 경남대학교 산업경영연구소 2021 지역산업연구 Vol.44 No.3

본 연구는 국내 자동차 산업을 대상으로 코로나19 이전인 2019년과 코로나19 시기인 2020년의 경영효율성을 비교분석하였다. 분석을 위해 자료포락분석(Data Envelopment Analysis)를 이용하였으며, 투입요소로는 종업원 수, 비유동자산, 총자본을, 산출요소로는 매출액과 당기순이익, EBITDA을 사용으로 분석을 실시하였다. 분석 결과 코로나19를 겪은 2020년 자동차 산업의 효율성 평균은 CCR 값이 0.623, BCC 값이 0.757로 조사되어 전년과 큰 차이가 없었다. 다만 CCR값 기준 54.2%의 기업들의 효율성 값이 감소되었음을 알 수 있었다. 규모효율성 분석 결과, IRS가 10.4%, DRS는 66.7%, CRS는 22.9%로 나타나 기업 규모에 따라 효율성의 차이가 있음을 검정하였다. 코로나19로 인해 국내자동차 산업의 많은 기업들이 타격을 받아 경영효율성이 악화되었으며, 투입요소를 줄이는 것을 통해 효율성을 개선시켜야 함을 알 수 있다. This study analyzed the management efficiency of the automobile industry in 2019 and 2020 before COVID-19. The analysis was done using DEA, and input factors were the number of employees, total capital, and non-current assets, and output factors were sales, net income, and EBITDA. As a result of the analysis, looking at the average efficiency of the automobile industry in 2020, which suffered from Corona 19, the CCR value was 0.623 and the BCC value was 0.757. The efficiency value of 54.2% of DMUs based on the CCR value decreased. As a result of the scale efficiency analysis, IRS was 10.4%, DRS was 66.7%, and CRS was 22.9%. Also, as a result of the non-parametric test, there was a difference in efficiency according to the size of the company. As a result of the study, the management efficiency of many companies in the domestic automobile industry has deteriorated due to COVID-19, and efficiency should be improved by reducing input factors.

비모수 검정을 활용한 자동차 기업의 상대적 경영 효율성 평가

하귀룡 ( Gui Ryong Ha ),최석봉 ( Suk Bong Choi ) 한국지식경영학회 2014 지식경영연구 Vol.15 No.2

This paper investigated the efficiency of automobile firms by using several non-parametric approaches. First, using Data Envelopment Analysis (DEA), the paper has investigated the critical factors that determine the relative efficiency of management performance in automobile companies. Second, we examined how the firm size impact on the difference of this efficiency by using Kruskl-Wallis Test. Third, by using Mann-whitney test, we also investigated the difference of the efficiency accoss existence of technological innovation activity. Finally, the paper explored the relationship between technological innovation and management efficiency by using logistic regression model. The findings of this study provided practical information for inefficient automobile firms to find benchmarking firms and strategic position to improve their efficiency. The result also provided theoretical and methodological implications for those who explore factors affecting management efficiencies. Future research directions with the limitation of the studyare discussed.

DEA 모형을 이용한 국내 물류기업의 경영효율성 분석

하귀룡(Ha, Gui Ryong) 영남대학교 산경연구소 2012 영상저널 Vol.4 No.2

본 연구는 국내 물류산업 기업의 효율성을 분석 및 평가하고, 이러한 분석 정보를 통하여 해당 기업의 경영자와 투자자 그리고 기업평가 의사결정자에게 유용한 정보를 제공하고자 한다. 특히 본 연구에서는 기존의 효율성 분석에서 이용된 변수들 뿐만 아니라 다른 변수들도 포함하여 효율성을 측정함으로 보다 실질적인 경쟁력강화 방안을 모색하고자 한다. 일반적으로 효율성 분석에 가장 많이 이용되고 있는 자료포락 분석(data envelopment analysis, 이후 DEA)을 활용하여 국내 증시에 상장된 국내 물류기업의 효율성을 기술적, 규모적 특성 측면에서 측정하였다. 또한 효율성 측정을 통하여 벤치마킹 대상기업(best practice firm)을 발굴하고 이를 통해 개별기업이 경영활동을 효율적으로 수행하는 데 필요한 구체적 정보를 제공하고자 한다. 연구대상 기업에 대해 CCR 모형과 BCC 모형을 적용하며 효율성을 분석한 결과, CCR 모형에서 효율성의 값이 1.00인 기업은 모두 2개(7.6%)이며, BCC 모형에서 효율성이 1.00인 기업은 모두 9개(34.6%)로 측정되었다. This paper contributes to the understanding of firm level dynamics of management efficiency in Korean logistics industry in following ways. This study investigates the management efficiency of firms in logistics industry based on a data envelopment analysis(DEA) approach. I applied number of employee, fixed assets and gross capital as impurt factors while the total sales and net profit as output measures. In particular, examined the management efficiency across logistics industry firms according to their sales scale and types of production process. This paper contributes to the understanding of firm level dynamics of management efficiency in Korean logistics industry. By considering industry specific features of logistics firms, I have assessed relative technical and scale efficiencies of management. Accordingly, this paper identifies the best practice of firms for benchmarking purpose to improve their management efficiency.

국내 주요 광고주의 광고비 효율성 분석

하귀룡(Ha, Gui-Ryong),이경탁(Lee, Kyung-Tag) 대한경영학회 2011 大韓經營學會誌 Vol.24 No.6

자료 포락분석을 이용한 100대 광고기업의 효율성 분석

하귀룡(Gui-Ryong Ha),이경탁(Kyung-Tak Lee),손창환(Hwan-Chang Son) 한국의사결정학회 2010 의사결정학연구 Vol.18 No.1

본 연구는 자료포락 분석(이후 DEA)을 이용으로 국내 광고비 100대 기업의 효율성을 분석하였다. DEA모형들 중에서 CCR 모형과 BCC 모형을 이용하여 분석을 실시하였으며, 투입변수로는 TV 광고비, 라디오 광고비, 신문 광고비, 잡지 광고비를 설정하고 산출변수는 매출액로 하였다. 또한 투입변수와 산출변수와의 타당성은 상관관계 분석을 통하여 검증하였다. DEA 모형에 의한 측정결과에 따르면, CCR 모형에서 평균 효율성은 21.5%, BCC 모형에서의 평균 효율성은 69.3%, 규모 효율성의 평균은 29.2%로 측정되었다. 또한 비효율기업이 가장 많이 벤치마킹할 수 있는 기업은 CCR 모형에서는 한국존슨앤드존슨이고 BCC 모형에서는 현대자동차그룹이 측정되었다. 본 연구의 시사점은 국내 기업들 중 광고비 순위 100대 기업들을 대상으로 DEA 모형을 이용한 연구는 거의 없는 상황에서 국내 기업의 경쟁력 제고에 활용할 수 있는 유용한 연구라고 할 수 있다. The purpose of this study is to analysis the advertising efficiency of 100 advertiser by Data Envelopment Analysis(DEA). We use DEA-CCR and DEA-BCC model. Four items such as TV, radio, newspaper, and magazine advertising expenditures are selected as inputs, and sales are selected as outputs. Validity is verified by correlations between input variables and output variables. According to results, efficiency in CCR model, efficiency in BCC model, and size efficiency average are 21.5%, 69.3%, and 29.2%. In practical implications, this study evaluates the advertising efficiency of 100 advertiser using DEA and offers useful method to increase advertising efficiency.

일반 논문 : 국내 ICT중소기업의 경영효율성 분석: 상장기업을 중심으로

하귀룡 ( Gui Ryong Ha ),최석봉 ( Suk Bong Choi ) 한국중소기업학회 2011 中小企業硏究 Vol.33 No.4

본 연구는 우리나라 대표적인 전략산업이라 할 수 있는 ICT 산업에 종사하는 종소기업들의 경영효율성에 관한 것이다. 국내 ICT 산업의 경쟁력강화가 국가경쟁력의 핵심이라는 인식이 널리 공유됨에도 불구하고 이들 기업에 대한 경영효율성 분석이 체계적으로 이루어지지 않은데 착안하여, 산업 내 중소기업을 대상으로 경영효율성을 분석하였다. 기존의 대부분의 효율성 분석연구들이 1개년도의 횡단면 자료를 이용하는 것과 달리, 2006년부터 2009년까지 4개 년도를 대상으로 함으로써 국내 중소 ICT 기업 효율성의 동적인 변화추세와 그 의미를 보다 정확히 찾고자 하였다. 또한 기존연구에서 실시한 효율성 분석에서는 투입요소로서 매출원가 중심으로 고려하였으나, 본 연구에서는 연구개발비를 기업의 장기적인 투자와 영업에 관련된 고정자산과 함께 고려함으로 연구개발 및 기술혁신활동이 여타 다른 산업에 비해 활발한 ICT 산업의 특성을 반영한 효율성 분석을 실시하였다. 분석결과를 통하여 벤치마킹 대상기업을 발굴하고 이를 통해 개별 ICT 중소기업이 효율적으로 경영을 수행하는데 필요한 정보를 제공하고 보다 체계적인 효율성의 근거와 개선점을 도출하였다. The growth of the Information Communications and Technology (ICT) industry in Korea over last 20 years is recognized as a significant factor for the sustainable growth of the Korean economy as a whole. The Bank of Korea reported that 40% of the total GDP growth rate is attributed to the ICT industry. The main reasons of such impressive performance are proactive policy support by the Korean government and continuous efforts of ICT firms for R&D and technological innovation. Although there is a general consensus that the small and medium sized enterprises (SMEs) play a critical role for the improvement in the competitiveness of the Korean ICT industry, little empirical analysis of management efficiency on the ICT SMEs has been done since the 2008 financial crisis and global recession. Thus, this research attempts to measure and analyze management efficiency based on data envelopment analysis (DEA) models. In particular, recognizing the significance of technological innovation for the competitiveness of ICT SMEs, we applied R&D expenditure with fixed assets and numbers of employees as input factors and highlighted their role in evaluating efficiency. Several contributions of this present study are noteworthy. First, our study investigates the increasing role of SMEs in the process of development of ICT industry in Korea. This is in contrast to the previous research of management which has mostly focused on large firms. We attempt to identify the best practice of SMEs for benchmarking purposes to improve their management efficiency. Second, our study is longitudinal. By using 4 different years of longitudinal data, this study conducts rigorous tests of the key factors affecting management efficiency and their trends over years. Third, by applying R&D expenditure with fixed assets and employee size as alternative input factors, we provide several plausible alternative explanations on the role of long term investment and technological innovation capability on the management efficiency in Korean SMEs. The ICT firms have been active in long term R&D investment for their competitiveness. We consider this industry specific factor for the analysis of management efficiency. The paper is organized as follows. Section 2 provides theoretical background. It includes a critical review of the ICT industry and management efficiency research on SMEs. Section 3 defines the DEA model, including input and output measures. Section 4 identifies the best practices of the frontier firms surveyed in this study. We also present the main results of empirical analysis. A conclusion with some theoretical and practical implications is presented in Section 5. Our research results suggest that there exists a close internal relationship between R&D, fixed assets and employee size and sales, which is an output measure, and their inherent relationship makes efficiency scores closer to 1. The results show that less than 10 percent of the firms are fully efficient in R&D and management activities and that more than two-thirds are at the stage of increasing returns to scale. More specifically, results obtained in our CCR model of DEA analysis show average technical efficiency (TE) in the range of 33~47% over the four years surveyed. Hence it implies that firms operating at the correct scale could save up to 33~47% of their inputs to produce the same amount of output. Secondly, applying the BCC model, the average of pure technical efficiency (PTE) scores are in the range of 58%~74% over the years estimated. The scores suggest that a much larger number of DMUs becomes efficient, implying that the model did not correctly discriminate among efficient and inefficient units. Thirdly, scale efficiency (SE) scores on average are higher than TE and PTE scores for the same years, distributed between 59% -77%. This result suggests that inefficiency from internal operation of firms is much more severe. Finally, when we consider the efficiency scores by the multiple years surveyed, it shows that the score has been gradually reduced. For instance, the findings indicate that 17.2% of the enterprises achieve CRS scores of over 0.8 in 2006 while it reduced to 13.8% in 2007 and 10.3% in 2008 and 2009. This implies that global economic crisis has comprehensively impacted the ICT market since 2008, which constricted firms` long term investment and sales growth. Despite previous academic efforts to investigate the successful growth of ICT industry in Korea, the increasing role of ICT SMEs in such development have rarely been analyzed, especially from the management efficiency perspective. Previous studies have not attempted to examine the effects of technological innovation activities as an important factor for management efficiency analysis. The relevant literature has focused primarily on efforts as determinants of R&D and management performance. Little attention has been given to the effective use of resources, particularly at the SMEs level. They also show considerable limitations by using cross sectional data or focusing on large firms. This paper tries to fill these gaps by developing an alternative approach to the evaluation of management efficiency of the ICT industry with particular reference to ICT SMEs and using panel data over four years. This study also highlights the distinctive results from three different models to evaluate management efficiency (i.e. TE. PTE and SE), and incorporate them to provide better implication for firms who improve their efficiency. For instance, our research suggests that inefficient firms can improve their efficiency through not only a reduction of R&D expenditures, number of employees and fixed assets, but also increasing R&D and enlargement of employment since firms show different results of efficiency features depending on the consideration of scale effects. This paper contributes to the understanding of firm level dynamics of management efficiency in the Korean ICT industry. By considering industry specific features of ICT firms which are more proactive in R&D than others, we have assessed relative technical and scale efficiencies of management and R&D resources across ICT SMEs. The findings of the paper have significant policy implications to innovation strategy and management policy for ICT firms and other technology-intensive industries that require continuous improvement in management efficiency for a competitive advantage. The study has several limitations that may be addressed in future research. Firstly, we measured output factor by using sales data. However, not all firms pursue sales growth as their purpose of management. Some may prefer to maximize net profit or develop new technological capabilities. Thus, we suggest that future studies should use more fine-grained decomposition of the various forms of output measures. Secondly, as our study focused on investigating relative management efficiency scores, future studies may analyze what factors affect management efficiency. Thirdly, the generalisability of the findings are limited by our use of one industry and stock listed firms for the research context. Future works should aim to address these limitations by considering different industries, large firms as well as SMEs, stock listed firms and non-listed firms. These extensions would further develop our understanding of management efficiency of SMEs in relation to innovation activities.

제품조달시간 제약을 가지는 주문에 대한 생산 및 배송 일정계획

하귀룡(Gui Ryong Ha),박현재(Hyun Jai Park),전재호(Jaeho Juhn),윤상흠(Sang Hum Yoon) 한국산업경영학회 2008 경영연구 Vol.23 No.1

본 연구에서는 주문생산방식(make-to-order)에서 고객들로부터 접수된 주문(order)들을 모두 처리하는데 소요되는 최종 완료시간을 최소화할 수 있는 주문간 생산 및 배송 순서를 결정하기 위한 주문일정계획모델(order scheduling model)을 고려하고 있다. 각 주문은 자체생산품과 외부조달품으로 구성되고, 자체생산품에 대해서는 독자적인 생산일정계획이 필요하지만, 외부조달품의 경우에는 외부에서 조달되며, 정해진 조달완료시점에 도착한다. 또한, 각 주문에 속한 제품들이 모두 준비된 이후에는 고객으로의 배송이 이루어지게 된다. 본 연구에서는 이러한 운영상의 구조를 생산 및 조달단계와 그 이후의 배송단계로 연결되는 2단계 모델로 구성하고 배송단계에서의 배송시간과 배송차량의 가용성에 따라 3가지 변형모델로 구분하여 각 모델에 대한 경영과학적 해법을 제공하고자 한다. 각 모델에서 해에 대한 우월성질들을 개발하고 최종 완료시간을 최소화 할 수 있는 최적 일정계획법을 제안한다. 특히, 마지막 모델에 대해서는 근사해를 제공하는 3가지 발견적 해법(heuristic)을 제안하고, 각 해법의 성능을 여러 가지 수치데이터에 대한 실험을 통해 검증하였다. This paper considers a coordinated production and delivery scheduling problem to minimize the maximum completion time of a finite number of orders received from customers. Each order consists of two types of products. One type is manufactured by an in-house facility, but the other type is outsourced from the outside facility(or, subcontractor) so that the available time of the outsourced product is given as positive lead time. After all the products belonging to each order are prepared, the order is delivered to customer. The completion time of each order is measured by the time when delivery of the order is completed. The objective of this paper is to find out optimal production and delivery schedule minimizing the maximum completion time of all orders. We suggest three different models according that whether the delivery times to each customer are different or not, and that whether the capacity of delivery vehicle is finite or not. In the problem analysis, we first characterize some solution properties and then derive simple methods to find out the optimal schedules for the model 1 and 2. For the last model 3, a branch and bound solution is suggested and efficient heuristic algorithms to find approximate solutions are also developed. The performances of the proposed heuristics are evaluated through numerical experiments.

국내 철강산업의 효율성분석에 관한 연구: 기술혁신요소를 중심으로

하귀룡 ( Gui Ryong Ha ),최석봉 ( Suk Bong Choi ) (주)엘지씨엔에스(구 LGCNS 엔트루정보기술연구소) 2012 Entrue Journal of Information Technology Vol.11 No.2

본 연구에서는 글로벌 경기침체 이후, 최근 국내 철강산업의 효율성을 DEA(Data Envelopment Analysis)을 이용하여 분석하였다. 기존의 연구와 달리 첫째, 철강산업의 기술혁신 측면을 다른 요인들과 함께 고려하여 효율성을 분석함으로 철강기업들의 경쟁력을 강화하기 위한 보다 유용한 시사점을 제공하고자 했다. 둘째, 분석방법에 있어서는 DEA 모형 중에서 CCR 모형과 BCC 모형을 사용하였으며, CCR 모형과 BCC 모형에 의한 효율성 측정뿐만 아니라 평가 대상 DMU에 대한 규모의 경제에 의한 효율성분석도 추가로 실시하였다. 셋째, 효율적 DMU(Data Making Unit)들을 대상으로 Super Efficiency Model을 통한 순위 분석도 함께 실시함으로 보다 정확한 효율성분석을 시도하였다. 마지막으로 본 연구에서는 DEA 분석 통하여 얻어진 경영효율성 값을 활용하여 기술혁신활동수준이 높은 기업일수록 경영효율성이 높다는 사실을 추가적인 회귀 분석을 통하여 실증함으로 기존연구들이 기술혁신활동과 기업의 기술적 · 재무적 성과와의 관계에 집중하여 기술혁신활동의 중요성을 설명하여 왔는데 이러한 연구를 보완하는 데 기여하고자 하였다. 결론적으로 본 연구는 기술혁신을 수행함에 있어서 매출액 증대에 도움이 될 수 있도록 철강기업들에게 비효율의 크기, 벤치마킹해야하는 효율적인 기업들, 효율적 기업이 되기 위해 줄여야 하는 투입요소들, 규모의 경제 혹은 비경제에 대한 해답을 제공하였다. Although there is a general consensus that the steel industry plays an critical role in the development of Korean economy, little empirical analysis of efficiency on the steel companies has done after global economic recession of 2008. Thus, this research attempts to measure and analyze their efficiency based on DEA models. In particular, recognizing the significance of technological innovation for the competitiveness of firms, we applied determinants of technological innovation as input factors and highlighted their role in measuring efficiency. By using Super Efficiency Model with CCR and BCC models, our study provide more precise information as well as practical implication for inefficient firms to find benchmarking firms and to improve their efficiency.